In gas turbine engines, the high degree of performance is very critically dependent upon the physical and mechanical properties of its component parts; for example, seals, casings, seal shroud support rings shafts and the like. These parts must have very critical thermal expansion and strength characteristics to ensure efficient performance of the engine. Thermal stability and aging are equally critical properties for efficient service.
A major portion of the known highly alloyed or superalloy nickel-base alloys was an outgrowth of the basic "80-20" nickel-chromium alloy. Many developments were made to the basic 80-20 system with additions of one or more modifying elements, such as tungsten and molybdenum, to improve certain properties of the alloy. Thus, the prior art is replete with nickel-base alloys containing about 15 to 25% chromium and up to about 12% modifying elements, especially molybdenum.
Known in the art for use in the production of various engine parts are three prior art alloys as described in Table 1. The alloy compositions appear to be similar. The criticality of seemingly minor compositional differences is evident as each alloy excels in specific properties. Because of this, there is an urgent need for an alloy that provides a favorable combination of various properties.
An alloy with a broad range of properties would be suited for other severe service uses such as (1) parts for rocket engine thrust chambers and fuel manifolds; (2) high strength fasteners; (3) high temperature springs and (4) dissimilar welding and repair of gas turbine and fossil power plants.